Short answer
Once you’ve given notice of appeal against a closure notice, discovery assessment, penalty determination or information notice, you have three options: ask HMRC to carry out its own internal review of the decision, accept a review if HMRC offers one first, or notify the appeal directly to the independent tax tribunal. Both the review route and the direct-to-tribunal route run on strict 30-day deadlines, and mediation — HMRC calls it Alternative Dispute Resolution — can be used alongside either one without giving up your right to appeal.
Applies to
- Schemes
- Merged scheme · ERIS · Legacy SME · Legacy RDEC · All periods
- Periods
- 1 April 2009 onwards
- Claimants
- All
Giving notice of appeal
Before any of the routes below become relevant, you have to appeal the decision itself. For a closure notice or discovery assessment, that means giving HMRC written notice of appeal within 30 days of the decision, specifying your grounds — see What happens if HMRC opens an enquiry into my R&D claim? for closure notices and Can HMRC reopen my R&D claim after the enquiry window has closed? for discovery assessments. The requirement to state your grounds in the notice of appeal is common to every appeal under the Schedule 18 machinery — it’s worth being specific here, because it frames the dispute for everything that follows.
Your three options once you’ve appealed
After HMRC gets your notice of appeal, one of three things happens next:
- You ask HMRC for a review. You have 30 days from giving notice of appeal to request that HMRC’s own review team — a different officer from the one who made the decision — looks at it again. HMRC can’t refuse a request made in time, though it can agree to a longer period with you if there’s a good reason to wait.
- HMRC offers you a review. HMRC can offer a review without being asked. If it does, you have 30 days to accept it. If you don’t respond within that window, the offer lapses and the original decision stands unless you notify the tribunal instead.
- You notify the appeal straight to the tribunal, skipping the review stage entirely.
You can’t do more than one of these for the same appeal — once you’ve asked for a review, or the tribunal, you can’t switch tracks except in the limited way described below.
How the review works
The reviewing officer looks at the decision afresh and reaches one of three conclusions: upheld (the original decision stands), varied (changed, in whole or part) or cancelled. HMRC has 45 days from the day the review starts to notify you of its conclusion — or a longer period if you’ve agreed one. Miss that deadline, and the review is treated as concluded in HMRC’s favour — the original decision is deemed upheld — and HMRC then has to write and tell you that’s happened.
This deadline is worth diarising in its own right. It’s easy to assume a stalled review is drifting in your favour while HMRC works through it; the opposite is true if the 45 days lapse without a conclusion notice. A review conclusion, once reached, is treated in the same way as a written settlement agreement between you and HMRC — it isn’t simply advisory.
A review doesn’t reopen everything from scratch. It’s a check on the specific decision under appeal, carried out by someone who wasn’t involved in making it, not a fresh enquiry into the whole claim.
Notifying the tribunal
You have 30 days from the date of HMRC’s review conclusion notice — or, if no notice arrives, 30 days from the day after the 45-day review period (or any agreed extension) expires — to notify your appeal to the tribunal. If you notified straight to tribunal without going through a review first, the same 30-day clock runs from your original notice of appeal instead. Miss the window either way, and you need the tribunal’s permission to notify late, which isn’t guaranteed.
The tribunal allocates appeals into one of four categories: default paper (decided on the papers, no hearing — low-value penalty appeals mainly), basic (a shorter hearing, typically by video), standard (anything not fitting the other three — where most contested R&D technical disputes land) and complex (cases needing lengthy or technical evidence, raising an important point of principle, or involving large sums). A case is allocated to complex only where it meets that test on its own facts; the size of the R&D relief in dispute is a factor, not an automatic trigger. Complex allocation matters practically because it’s the one category where the losing side can be ordered to pay the other side’s costs — outside complex cases, each side generally bears its own costs regardless of outcome, which is part of why the tribunal route is realistically available to smaller claimants in a way that ordinary civil litigation isn’t.
Alternative Dispute Resolution (ADR)
ADR is HMRC’s mediation facility — a trained HMRC mediator, independent of the officer handling your case, works with you and HMRC to see whether the dispute can be narrowed or resolved without a tribunal hearing. The mediator doesn’t decide the dispute or take responsibility for it; their role is to restart communication and help both sides focus on what needs resolving.
ADR is available both during a compliance check that has stalled and after an appealable decision has been made — including alongside a statutory review, or after you’ve already notified the tribunal. You apply online or by phone; HMRC tells you within 30 days whether it’s accepted, and if it is, both sides commit to meeting within 90 days of acceptance.
Critically, applying for or taking part in ADR does not affect your right to appeal or to request a statutory review, and it does not itself extend any of the deadlines above. Treat it as something that runs alongside the formal process, not a substitute for protecting your appeal and tribunal-notification deadlines while it’s ongoing.
ADR isn’t available for every dispute — it’s excluded for default paper and basic tribunal cases, avoidance and criminal matters, debt recovery, and a handful of other specific categories, so check eligibility before assuming it’s an option. If it doesn’t resolve the dispute, the mediator’s role ends, and the normal appeal route—review or tribunal—continues from wherever it got to.
Worked example
A company receives a closure notice removing £180,000 of claimed relief across two projects, on the basis that HMRC doesn’t accept that a technological uncertainty existed. The company’s adviser considers the technical position strong and doesn’t expect HMRC’s review team to take a materially different view from the officer who closed the enquiry — reviews are useful where a decision turns on a judgement call or an overlooked fact, less useful where it turns on a genuine, well-argued difference of technical opinion that a second HMRC officer is unlikely to resolve differently (Vantage has experience of this precise scenario). The company notifies the appeal directly to the tribunal instead of requesting a review, and because the dispute is a genuine, evidence-heavy disagreement about the science rather than a routine penalty point, the case is allocated to the standard category. Before the hearing is listed, the company also applies for ADR; HMRC accepts, and the mediated meeting narrows the dispute to one of the two projects, which the parties settle by agreement. The tribunal notification for the remaining project stays live throughout — nothing about applying for ADR paused or removed it — and only the unresolved project proceeds to a hearing.
In our experience, if you apply for a tribunal, HMRC will propose ADR back to the client. This happened in our recent compliance check with Advent Insurance Management,
Where claims go wrong
- Missing the 30-day window at any of the three stages — the original notice of appeal, the request for review, or notifying the tribunal after a review concludes. Each is a separate clock, and missing any one of them shifts you from arguing the technical merits to first arguing for permission to be let back into the process at all.
- Assuming a stalled review is going quietly in your favour. It’s the opposite: if HMRC misses the 45-day review deadline, the original decision is deemed upheld, not cancelled.
- Treating ADR as pausing the clock. It doesn’t. A company that stops tracking its tribunal-notification deadline because ADR is “in progress” can lose the right to notify at all if the mediation runs past it without a resolution.
- Reflexively requesting a review on every case, regardless of what’s actually in dispute. A review adds real value where a decision turns on a fact HMRC’s officer may not have weighed properly, or a straightforward misapplication of the rules. It adds much less where the dispute is a genuine, well-evidenced technical disagreement that a differently-instructed review officer is unlikely to see differently — and it uses up time against the eventual tribunal deadline while doing it.
- Not separating “we disagree with HMRC” from “HMRC hasn’t followed its own process.” The grounds of appeal you give at the outset shape what the review or tribunal is actually being asked to decide — see What happens if HMRC opens an enquiry into my R&D claim? on why a specific, considered notice of appeal matters from the outset rather than being treated as a formality.
John Mapother
Founder & Director
Last reviewed 2 September 2026